Front Disc Brakes

Older brake pads or shoes may contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air. Avoid inhaling any dust from any brake surface. When cleaning brake surfaces, use a commercially available brake cleaning fluid. GM suggests a water dampened cloth or water-based solution be used to remove any dust on brake parts, to prevent any asbestos fibers from becoming airborne.

Fluid pressure behind the caliper piston(s) increases when applying the brakes. Pressure exerts equally against the bottom of the piston(s) and the bottom of the piston bore(s). The pressure applied to the piston transmits to the inner pad. The pressure forces the pad against the inner rotor surface. The pressure applied to the bottom of the piston bore(s) forces the caliper to slide on the mounting bolts. The caliper slides to the center of the vehicle. Because the caliper is one piece, the sliding movement causes the outer section of the caliper to apply pressure against the back of the outer pad. The pressure then forces the pad against the outer rotor surface. As line pressure builds, the pads press against the rotor surfaces with increased force. The force brings the vehicle to a stop. When releasing the brake pedal, the line pressure releases. The seal and seal groove cause the piston to retract slightly. Piston retraction causes less drag on the rotor by both pads. Outward movement of the piston and inward movement of the caliper automatically compensate for pad wear. As the pads wear, the increased area behind the piston fills with brake fluid from the master cylinder reservoir.